Manipulating the electronic properties of Cd3P2: An ab-initio investigation G. Jaiganesh and S. Mathi Jaya Materials Science Group, Indira Gandhi Centre for Atomic Research, Kalpakkam – 603 102, Tamil Nadu, India Author’s E-mail: jaiganesh@igcar.gov.in; smathi@igcar.gov.in RESULTS AND DISCUSSION Magnetic semiconductors are promising materials in magneto-electronic and sensing devices. They offer the possibility of manipulating the charge and spin of the electron simultaneously [1]. Intensive research in this area has lead to the identification of several transition metal substituted magnetic semiconductors [2]. Best known diluted magnetic semiconductors with room temperature ferromagnetism belong to the III-V, II-VI and IV-VI groups [3]. The formation of magnetism in semiconductors by the introduction of nonmagnetic elements is an interesting feature in this area and it has acquired considerable interest in the recent years [4]. INTRODUCTION Two Ti atom substituted Cd3P2 One Ti atom substituted Cd3P2 C(n,r) = n! / ( r!(n - r)! ) consideration of all the possible configurations Two ways of replacing two Cd atoms by two Ti atoms are: the case of replacing two Cd atoms by two Ti atoms among the positions corresponding to a selected 8g symmetry the case replacing two Cd atoms by two Ti atoms among the positions corresponding to two distinct 8g symmetries. complex task 84 (First Way) + 240 (second way) = 324 (net ways of replacement) considered 7 cases of replacing two Cd atoms within the positions represented by specified 8g symmetry by two Ti atoms considered 15 cases of replacing two Cd atoms at positions represented by two distinct 8g symmetries with two Ti atoms Cd atoms occupy 3 distinct 8g positions A Ti atom can be substituted among any three distinct 8g positions II-V compounds have unusual transport and photo-voltaic properties. Cd3P2 is an exceptional semiconducting material that has applications in photovoltaic, bio-labeling and opto-fluidic sensors [5, 6]. Manipulating the electronic structure of Cd3P2 through the dilute doping of transition metal atoms is an efficient way to alter the electronic properties of the system which can enlarge its application potentials. II-V COMPOUND SEMICONDUCTORS The second case of replacing two Ti atoms is taken at random. Total energy calculations The Ti replacement at the third distinct 8g positions lead to minimum total energy. Calculated total energy differences (∆E) in eV, the heat of formation (∆H) in eV and net magnetic moment in µB Compound ∆E ∆H Net Magnetic Moment Cd2.875Ti0.125P2 -0.0392 -0.228 1.315 Cd2.75Ti0.25P2 -0.0535 -0.231 2.138 Heat of formation, Our present interest is on the investigation of the magnetism of the Cd3P2 induced by the nonmagnetic Ti elemental substitution. DOS of Cd3P2, Cd2.875Ti0.125P2 and Cd2.75Ti0.25P2 Crystal Structure of Cd3P2 compound Primitive Tetragonal Lattice - P42/nmc (No.: 137) - 40 atoms (24 Cd and 16 P) per unit cell [7]. There exist three different type of cation atom Cd (1), Cd (2), Cd (3) and they occupy 8g sites of the space group P42/nmc whereas the anion P(1), P(2), P(3) atoms occupy the 4c, 4d and 8f sites respectively. One/two Ti atom in Cd3P2 leads - conduction explores - magnetic moment – originates-3d electrons of the Ti atom. the one/two Ti atom substituted systems prefer ferromagnetic ordering “Magnetoelectronics”, edited by Mark Johnson, 1st Edition, Elsevier Academic Press, Amsterdam, 2004. “Handbook of Spintronic Semiconductors”, edited by Weimin and Irina Buyanova, Singapore: Pan Stanford Publishing, 2010. T. Dietl and H. Ohno, Reviews of Modern Physics, Vol. 86, 187-251 (2014). Jiji Antony et al., IEEE Trans. on magnetic, Vol. 42, No. 10, 2697-2699 (2006). Shiding Miao et al. Adv. Optical Mater. 3 (2015), pp. 187–193. Liping Ding et al. Cryst. Eng. Comm., 16 (2014), pp. 9622–9630 P. Villars and L. D. Calvert, “Pearson’s hand book of Crystallographic data for Intermetallic Phases” Materials Park, OH: ASM International, Vol. 4, 4864 (1991). http://www.vasp.at/ REFERENCES CONCLUSION In this work, we have studied the influence of the partial substitution of Ti atoms at Cd sites on the electronic structure and magnetic properties of Cd3P2 using the ab-initio techniques. We found that Ti atom substitution can induce magnetic property in the Cd3P2 semiconductor. The one/two Ti atom substituted Cd3P2 is more stable in the ferromagnetic phase . CALCULATIONAL DETAILS The DFT as implemented in VASP along with PAW pseudo-potential is used for the calculations [8]. cutoff energy of 525 eV and 6×6×4 (for Cd3P2) and 8×8×6 (for substituted systems) k-point mesh is used. The optimization of the Cd3P2 and Ti substituted Cd3P2 structures were carried out. Spin-polarized calculations are performed using the spin interpolation scheme proposed by Vosko et al [8]. Acknowledgment One of the authors (G. Jaiganesh) wishes to thank the Council of Scientific and Industrial Research, New Delhi, India for the award of Research Associateship (Grant No.: 9/532(0026)/2013 EMR-1). Magnetic stability is calculated from the total energy difference (ΔE) of the primitive cell between AFM (or FM) and NM configurations.